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dc.contributor.authorGomez-de-Segura, G
dc.contributor.authorFairhall, CT
dc.contributor.authorMacDonald, M
dc.contributor.authorChung, D
dc.contributor.authorGarcia-Mayoral, R
dc.contributor.editorJimenez, J
dc.date.accessioned2020-12-07T10:50:57Z
dc.date.available2020-12-07T10:50:57Z
dc.date.issued2018-01-01
dc.identifier.citationGomez-de-Segura, G., Fairhall, C. T., MacDonald, M., Chung, D. & Garcia-Mayoral, R. (2018). Manipulation of near-wall turbulence by surface slip and permeability. Jimenez, J (Ed.) Third Madrid Summer School on Turbulence, 1001, (1), IOP PUBLISHING LTD. https://doi.org/10.1088/1742-6596/1001/1/012011.
dc.identifier.issn1742-6588
dc.identifier.urihttp://hdl.handle.net/11343/252856
dc.description.abstractWe study the effect on near-wall turbulence of tangential slip and wall-normal transpiration, typically produced by textured surfaces and other surface manipulations. For this, we conduct direct numerical simulations (DNSs) with different virtual origins for the different velocity components. The different origins result in a relative wall-normal displacement of the near-wall, quasi-streamwise vortices with respect to the mean flow, which in turn produces a change in drag. The objective of this work is to extend the existing understanding on how these virtual origins affect the flow. In the literature, the virtual origins for the tangential velocities are typically characterised by slip boundary conditions, while the wall-normal velocity is assumed to be zero at the boundary plane. Here we explore different techniques to define and implement the three virtual origins, with special emphasis on the wall-normal one. We investigate impedance conditions relating the wall-normal velocity to the pressure, and linear relations between the velocity components and their wall-normal gradients, as is typically done to impose slip conditions. These models are first tested to represent a smooth wall below the boundary plane, with all virtual origins equal, and later for different tangential and wall-normal origins. Our results confirm that the change in drag is determined by the offset between the origins perceived by mean flow and the quasi-streamwise vortices or, more generally, the near-wall turbulent cycle. The origin for the latter, however, is not set by the spanwise virtual origin alone, as previously proposed, but by a combination of the spanwise and wall-normal origins, and mainly determined by the shallowest of the two. These observations allow us to extend the existing expression to predict the change in drag, accounting for the wall-normal effect when the transpiration is not negligible.
dc.languageEnglish
dc.publisherIOP PUBLISHING LTD
dc.rights.urihttps://creativecommons.org/licenses/by/4.0
dc.source3rd Madrid Summer School on Turbulence
dc.titleManipulation of near-wall turbulence by surface slip and permeability
dc.typeConference Paper
dc.identifier.doi10.1088/1742-6596/1001/1/012011
melbourne.affiliation.departmentMechanical Engineering
melbourne.source.titleJournal of Physics : Conference Series
melbourne.source.volume1001
melbourne.source.issue1
dc.rights.licenseCC BY
melbourne.elementsid1326992
melbourne.openaccess.urlhttps://iopscience.iop.org/article/10.1088/1742-6596/1001/1/012011/pdf
melbourne.openaccess.statusPublished version
melbourne.contributor.authorChung, Daniel
melbourne.contributor.authorMacDonald, Michael
dc.identifier.eissn1742-6596
melbourne.event.locationMadrid, SPAIN
melbourne.accessrightsOpen Access


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